Affected by power outages due to tsunamis, storms and various other kinds of extreme weather, growing numbers of people around the world are thinking that it’s a good idea to generate at least some, if not all, the electricity they need at home and off-grid. Becoming even partially energy self-reliant is also seen as a way to hedge against the consensus view that electricity and fuel costs will be higher in the future than they are today, as well as insulation from price volatility.
While some are sticking to conventional diesel and fossil fuel generators, others are installing solar panels or micro-wind turbines with battery storage systems. Another option is emerging, as well: fuel cells. While home, or residential, fuel cell systems aren’t mainstream by any means, they’re increasingly being used to generate electricity across a wide variety of applications: from small- to medium-scale power plants down to portable consumer electronics. And they’re increasingly being viewed by home and building owners as a viable means of reliably producing clean energy.
How Fuel Cells Work
Similar to batteries in concept and design, fuel cells produce electricity via electrochemical reactions. In contrast to batteries, fuel cells produce electrical energy. They don’t store it. They need a constant stream of fuel and oxygen to continue producing electricity.
The basic workings of a fuel cell go like this. A fuel stream is directed into one fuel cell intake where it reacts with a catalyst on an electrode – the anode – to produce a stream of hydrogen ions and a stream of electrons, an electric current. The electric current is shuttled around a circuit and exits the fuel cell as direct current (DC) electricity.
While DC electricity can be and is used to power a range of household devices, a fuel cell’s electricity generally needs to be converted to alternating current (AC) here in the US. This is accomplished by running it through an inverter. The resulting AC can then be used to power lights, appliances, electronic equipment – any type of device that runs on AC power.
The hydrogen ions released at the fuel cell’s anode make their way from one electrode across an electrolyte made up of chemical elements or compounds through which the hydrogen ions can pass but the electrons can’t. Reaching the opposite electrode, the cathode, they react with oxygen in the air taken in through a second intake and produce water.
A Bit of Fuel Cell History
There are a variety of different kinds of fuel cells, though they all work in essentially the same way. One of, it not the oldest is the alkaline, or hydrogen, fuel cell, which was invented in 1839 by the Victorian Englishman Sir William Grove. Grove knew that passing an electric current through water would split the hydrogen and oxygen atoms it’s made of and send them off as gases. He reasoned that reversing the process would produce water and electricity.
Grove was right, but it took a bit of experimentation before he invented the device that proved his hypothesis. He called it a gas voltaic battery. Fifty years later, Ludwig Mond and Charles Langer were working on a more practical version of Grove’s invention to produce electricity, a device they called a fuel cell. In decades since, hydrogen fuel cells have been used famously to power NASA space missions.
Fuel cells got another big boost around the turn of the millennium, as scientists, engineers, business leaders, the public and politicians began to recognize and more fully appreciate the increasingly high economic and environmental costs of our seemingly insatiable appetite for energy in the form of fossil fuels. They were linked to development of a hydrogen economy, which by and large fell flat as the high costs of storing and transporting hydrogen, as well as their high manufacturing costs, became apparent.
Fuel Cells Today
Fuel cells are highly efficient, converting anywhere from 40% to more than 60% of the energy contained in the intake fuel to electrical energy. The most efficient diesel engine in the world has a peak energy conversion efficiency of nearly 52%. Peak conversion efficiencies of the latest Combined Cycle Gas Turbine (CCGT) power plants plants approach 60%, while that of modern thermal coal power plants peak at around 40%. Typical conversion efficiencies of gasoline-fueled automobile engines range around 20%-25%. Leading edge silicon solar panels’ peak energy conversion efficiency is approaching 20%.
Each type of fuel cell has its advantages and disadvantages. The following chart from the US Dept. of Energy’s (DOE) Fuel Cell Technologies Program summarizes their conversion efficiencies, as well as their advantages, disadvantages and other important characteristics.
Though tarnished and somewhat discouraged, governments, entrepreneurs and industry didn’t give up on fuel cells after all the hype surrounding the hydrogen economy faded away. Governments around the world continue to be a mainstay of research and development (R&D) funding. During the last ten years, the DOE’S Fuel Cell Technologies Program has spent over $2 billion, around 1% of its total budget, on fuel cell and hydrogen research, development and demonstration. “This is less than 2% of the global investment in the solar, wind and biomass industry in one year alone,” the DOE notes.
Academic and industry researchers continue to experiment with ways of building cheaper, higher performance fuel cells, and they’ve achieved notable success. A growing number of companies, both private and public, are selling increasing numbers of fuel cells to a wider variety of customers, including electric utilities, a growing range of industrial and commercial businesses and public and non-profit organizations. Adding to this list are home and building owners, a growing number of whom are viewing hydrogen fuel cells as a practical, reliable assurance against power outages.
The Stationary Fuel Cell Market
Fuel cells are being used in an increasingly wide range of applications, particularly when it comes to combined heat and power (CHP). South Korea is now home to what’s said to be the “world’s largest fuel cell park.” Anglo-American Platinum is using fuel cells for back-up electrical power to mine the platinum used as a catalyst in fuel cells – something of an ironic twist.
Thirty-four corporate customers have installed, deployed or purchased more than 250 fuel cell power systems and hundreds of backup power units with a total capacity of more than 30 MW, plus more than 1,000 fuel cell-powered forklifts, in a little over a year. The use of stationary fuel cells at mobile base stations for the wireless communications industry is forecast to grow rapidly, reaching 422,000 units by 2017, according to one market research report.
Taking the “greenest,” most environmentally friendly approach to their use, the city of Herten, Germany is using electricity from wind turbines to produce hydrogen via electrolysis. The hydrogen is stored for use and then run through fuel cells to produce electricity, a development that may turn out to be a major turning point in the transition to a “green” global energy economy.
Another particularly encouraging, integrated “green” application is up and running at the Orange County Sanitation District in Fountain Valley, California. There, biogas (methane) produced by wastewater treatment is ‘reformed’ in a fuel cell to produce the virtually pure hydrogen used by the fuel cell ‘stack’ to generate electricity to power the plant. Surplus hydrogen is refined even further, stored for use in fuel cell vehicles.
The Mobile Fuel Cell Market
Moving from stationary to mobile applications, a hybrid electric bus run by Oakland’s AC Transit recently set a record for durability by running more than 10,000 hours on its original fuel cell stack. More than 50% efficient, around double that of diesel-powered buses, the proton exchange membrane (PEM) fuel cell uses hydrogen fuel that isn’t produced from natural or biogas. As a result, AC Transit’s hydrogen fuel cell-powered hybrid electric buses emit nothing but water vapor. They produce zero greenhouse gas emissions and no particulates.
In personal transit, Toyota is just one global auto manufacturing multinational that recently announced it will invest more in fuel cell vehicle development. GM and Nissan are doing likewise.
In the UK, a small fleet of Microcab H2EV (Hydrogen-to-Electric Vehicle) vehicles was recently “delivered to Arup, leader of the CABLED (Coventry and Birmingham Low Emission Vehicle Demonstrators) project, for real-world testing and to determine if the technology fits into the UK’s existing infrastructure,” according to an Autobloggreen post.
Moving further down in scale, miniature, portable fuel cells for use in consumer electronics are being developed and tested. Shipments of portable fuel cells for portable electronics are expected to drive growth in the industry in the next five to ten years, according to a recent market research report.
Dialing down expectations a bit, “significant improvements in power density are required to enable the miniaturization necessary for fuel cells to be integrated directly into consumer electronics; only then are they likely to become part of our everyday lives in mobile phones and laptops,” according to the Fuel Cell Industry Today 2011 annual review. “If these advances can be realized and costs reduced, it would open up opportunities in a market expected to exceed $950 billion in 2011, according to the Consumer Electronics Association.”
Fuel Cells for the Home
Residential fuel cell use is growing as well. The recent spate of power outages and the increasing frequency of extreme weather events combined with expectations of higher, more volatile, energy costs is driving demand.
Residential fuel cell sales will double each year for the next six years, according to a recently released report, as they “gain increasing traction and generate significant revenue streams.” In Japan, Nagoya-base Toho Gas launched household fuel cell generators in May 2009. In September, it sold its 1,000th residential fuel cell.
Here in the US, the California Energy Commission relaunched its statewide incentive program for small wind turbines and fuel cells in early November. The Emerging Renewables Program was temporarily suspended in March as the commission investigated a suspected rebate fraud on the part of a small wind turbine manufacturer, bringing installation of both small wind turbines and fuel cells to a virtual standstill.
Total funds for the relaunched rebate program, estimated to be around $20 million, are being divided equally between fuel cell and small wind turbine market participants. New guidelines stipulate that rebates cannot exceed 50% of the net purchase price of the system.
As Hurricane Irene and Winter Storm Alfred blew in, buffeted the Northeast and cut power across the region, back-up fuel cell systems kicked in, providing electrical power to cell phone base stations, businesses including a tropical resort, a Whole Foods store and a Connecticut high school.
Power outages cost some $80 billion or more a year, according to an estimate from the Lawrence Livermore Berkeley National Laboratory. Able to reliably provide clean, off-grid electrical power efficiently, fuel cell industry participants continue to make advances in performance and in terms of lowering costs that may well result in homes and buildings around the country relying on fuel cells for off-grid, baseload electrical power in coming decades.
